<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN">
<html>
<head>
<!-- Copyright 1997 The Open Group, All Rights Reserved -->
<title>ungetwc</title>
</head><body bgcolor=white>
<center>
<font size=2>
The Single UNIX &reg; Specification, Version 2<br>
Copyright &copy; 1997 The Open Group

</font></center><hr size=2 noshade>
<h4><a name = "tag_000_010_265">&nbsp;</a>NAME</h4><blockquote>
ungetwc - push wide-character code back into input stream
</blockquote><h4><a name = "tag_000_010_266">&nbsp;</a>SYNOPSIS</h4><blockquote>
<pre><code>

#include &lt;<a href="stdio.h.html">stdio.h</a>&gt;
#include &lt;<a href="wchar.h.html">wchar.h</a>&gt;

wint_t ungetwc(wint_t <i>wc</i>, FILE *<i>stream</i>);
</code>
</pre>
</blockquote><h4><a name = "tag_000_010_267">&nbsp;</a>DESCRIPTION</h4><blockquote>
The
<i>ungetwc()</i>
function pushes the character corresponding to the wide-character code
specified by
<i>wc</i>
back onto the input stream pointed to by
<i>stream</i>.
The pushed-back characters will be returned by subsequent reads
on that stream in the reverse order of their pushing.
A successful intervening call (with the stream pointed to by
<i>stream</i>)
to a file-positioning function (.Fn fseek ,
<i><a href="fsetpos.html">fsetpos()</a></i>
or
<i><a href="rewind.html">rewind()</a></i>)
discards any pushed-back characters for the stream.
The external storage corresponding to the stream is unchanged.
<p>
One character of push-back is guaranteed.
If
<i>ungetwc()</i>
is called too many times on the same stream without an intervening read or
file-positioning operation on that stream, the operation may fail.
<p>
If the value of
<i>wc</i>
equals that of the macro WEOF, the operation fails and the input
stream is unchanged.
<p>
A successful call to
<i>ungetwc()</i>
clears the end-of-file indicator for the stream.
The value of the file-position indicator for the stream after
reading or discarding all pushed-back characters will be the same
as it was before the characters were pushed back.
The file-position indicator is decremented (by one or more) by each successful
call to
<i>ungetwc()</i>;
if its value was 0 before a call, its value is indeterminate after the call.
</blockquote><h4><a name = "tag_000_010_268">&nbsp;</a>RETURN VALUE</h4><blockquote>
Upon successful completion,
<i>ungetwc()</i>
returns the wide-character code corresponding to the
pushed-back character.
Otherwise it returns WEOF.
</blockquote><h4><a name = "tag_000_010_269">&nbsp;</a>ERRORS</h4><blockquote>
The
<i>ungetwc()</i>
function may fail if:
<dl compact>

<dt>[EILSEQ]<dd>
An invalid character sequence is detected, or a wide-character code does not
correspond to a valid character.

</dl>
</blockquote><h4><a name = "tag_000_010_270">&nbsp;</a>EXAMPLES</h4><blockquote>
None.
</blockquote><h4><a name = "tag_000_010_271">&nbsp;</a>APPLICATION USAGE</h4><blockquote>
None.
</blockquote><h4><a name = "tag_000_010_272">&nbsp;</a>FUTURE DIRECTIONS</h4><blockquote>
None.
</blockquote><h4><a name = "tag_000_010_273">&nbsp;</a>SEE ALSO</h4><blockquote>
<i><a href="fseek.html">fseek()</a></i>,
<i><a href="fsetpos.html">fsetpos()</a></i>,
<i><a href="read.html">read()</a></i>,
<i><a href="rewind.html">rewind()</a></i>,
<i><a href="setbuf.html">setbuf()</a></i>,
<i><a href="stdio.h.html">&lt;stdio.h&gt;</a></i>,
<i><a href="wchar.h.html">&lt;wchar.h&gt;</a></i>.
</blockquote><h4>DERIVATION</h4><blockquote>
Derived from the MSE working draft.
</blockquote><hr size=2 noshade>
<center><font size=2>
UNIX &reg; is a registered Trademark of The Open Group.<br>
Copyright &copy; 1997 The Open Group
<br> [ <a href="../index.html">Main Index</a> | <a href="../xshix.html">XSH</a> | <a href="../xcuix.html">XCU</a> | <a href="../xbdix.html">XBD</a> | <a href="../cursesix.html">XCURSES</a> | <a href="../xnsix.html">XNS</a> ]

</font></center><hr size=2 noshade>
</body></html>

